1. Field of the Invention
The present invention relates to an optical disc drive apparatus and servo control method for optical disc drive apparatus, and is preferably applied to an optical disc drive apparatus that supports a high density recording optical disc such as “Blu-ray Disc (Registered Trademark)”, for example.
2. Description of Related Art
An optical disc drive apparatus rotates an optical disc at high speed to record or reproduce information from the optical disc. Since the optical disc drive apparatus precisely performs a focus control and a tracking control for an optical pickup, a laser light from the optical pickup is precisely emitted to a track on a signal recording surface of the optical disc.
Some optical disc drive apparatuses are designed to emit, from the optical pickup, the laser light to the signal recording surface of the optical disc at an appropriate angle. Accordingly, its tilt actuator performs a tilt control to correct the angular displacement of an objective lens of the optical pickup with respect to the optical disc.
For example, Patent Document 1 (see Jpn. Pat. Laid-open Publication No. 2002-92919 [Page 4]) discloses an optical disc drive apparatus which performs a tilt control: The optical disc drive apparatus detects the acceleration of an external force against its body and then detects a radial tilt based on a distance from the center of the optical disc to a point where the laser light is emitted, a rotation speed of the optical disc and the acceleration.